The cop in the video shows extreme restrain and bravery while apprehending the suspect.

Alek was a mobile app developer who created an app called "Toronto Green Parking Advisor" downloaded more than 100 times. You can get it if you have an Android on Google Play. It seems like the app allows you to search for parking locations in Toronto near a given address. The address can either be your current location or an address you specify. Parking locations can either be viewed in a list or on a map.

Furious users went on the app's website after the attack to leave their negative reviews in the app comments section:

It seems like Alek really wanted to become a professional developer getting involved in Seneca’s Centre for Development of Open Technology development project at Seneca College.

Project states:

The program works by creating one or more objects and placing them on a Scene. It then adds one or more light sources and traces them as they reflect off or refract through objects.

So once again, noone knows why he did it. But it seems like mental illness could be at play. Some of his classmates at school described him as an odd and weird.